Diesters of oxo-alkanedioic acids can be used as an intermediate for the preparation of polyesters.
According to Japanese Patent Application 57 88,149 (1982), Application No. 80 162,878, dimethyl 4-oxo-heptanedioate (also referred to as "dimethyl .gamma.-oxopimelate") can be prepared by reaction of carbon monoxide, water and methyl acrylate in the presence of organic phosphorus compounds having one or more than one trivalent phosphorus atom bound to the organic residue and of cobalt carbonyls. Disadvantages of this known process are that pure CO is used, being a gas which is usually obtained by isolation from synthesis gas containing carbon monoxide and hydrogen, and that carbon monoxide is applied at a relatively high partial pressure.
It is an object of the present invention to prepare oxo-alkanedioic acids or diesters thereof in good yield and with a very high selectivity, starting from a gas containing carbon monoxide and hydrogen and using relatively low partial pressure of carbon monoxide.